Make Makefile fail when git information is not available

1 files changed, 7 insertions, 0 deletions

diff --git a/BUILD.md b/BUILD.md
index dba8b22f..711228d3 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -24,6 +24,13 @@ make build
 make release
 ```
 
+> :warning: Makefile uses git commands to determine the version and the
+> revision information for `fzf --version`. So if you're building fzf from an
+> environment where its git information is not available, you have to manually
+> set `$FZF_VERSION` and `$FZF_REVISION`.
+>
+> e.g. `FZF_VERSION=0.24.0 FZF_REVISION=tarball make`
+
 Third-party libraries used
 --------------------------